The invention relates to display arrangement comprising an electro-optical display medium between two supporting plates, a system of picture elements arranged in rows and columns, each picture element being constituted by two picture electrodes provided on the surfaces of the supporting plates facing each other, a system of row and column electrodes for driving the picture elements, the row electrodes being provided on one supporting plate and the column electrodes being provided on the other supporting plate, and a system of switching elements, a switching element being included between at least one row electrode and one column electrode in series with each picture element, which switching elements comprise at least one PIN diode having a mesa-shaped semiconductor body, which comprises in a sectional view transverse to a supporting plate in order of succession at least a first semiconductor region of a first conductivity type having a comparatively high doping concentration, a second semiconductor region of the first or a second conductivity type having a comparatively low doping concentration and a third semiconductor region of the second conductivity type having a comparativelY high doping concentration, the first and third semiconductor regions being provided with a connection conductor.
Such, a display arrangement is suitable to display alphanumeric and video information by means of passive electro-optical display media, such as liquid crystals, electrophoretic suspensions and electrochrome materials.
A display arrangement of the kind mentioned above is known from British Patent Application 2129183, in which a detrimental effect of ambient radiation on the operation of the display arrangement and especially on the switching elements is mentioned. If this switching element comprises one or more diodes, one of the requirements is that, when a reverse voltage appears at the diode, the current produced by the ambient radiation is as small as possible in order to ensure that the voltage across the picture element is maintained. In the said British Patent Application it is noted that with the configuration of diodes used therein, i.e. an anti-parallel arrangement of an equal number of diodes, the influence of the ambient radiation is partly eliminated. Further, it is noted in the said British Patent Application that the use of non-transparent conductors prevents light from penetrating into the semiconductor body.
A disadvantage of the known arrangement is that with the given form of the connection conductor a part of the ambient radiation, i.e. the light laterally incident on the semiconductor body, can still penetrate into the semiconductor body. It is technologically unattractive to shield incident radiation from all the side faces of the semiconductor body of a diode by covering it with nontransparent connection conductors.